Telephony.



E E. COFtWiN.

TEL'EHUNY. APPucATlQa mio muti. w13.

Patented June 8, 1915.

3 SHEETS-SHEET l.

4 Si SE S HIVENT 0R GF v ELMER R4 Cow/vm ,k BY- /l E. R. CORWN T'KELEPHONY. APPLICATIQN FELED APR.51 1913.

3 SHEETS-SHEET 2.

l BY y ATTORNEY LR. coawm..

' TELEPHONY.

APPLICAUON FILED APH. 51 i913.

1,141,937; Patented June s, 1915.

3 SHEETS-suur 3.

WHNESSE n INvEfIToR LMEB E.. CoRWi-N i STATES PATENT 'OFFICE if ILLINOIS, 'AssIGNoitfBY MESNE AssiGNMnN'isro FRANK?. cooxcoiitPANx, orfcnIcAGo,-ILLINIS, A conromi'rIoN ori-Inriiiqo'is.E 1-

' '.Toz-ZZ fw'omt'may concern:

' Be it known that I, vE Liiiniz 4Rf(DONWIN, residing atv --citizenV the United States, Chicago, iny .the-5..'countyf-of' lCook and State Aof Illinois, -have inyented 'a lcertain new andV :useful Improvement' in Telephony, of whichfollowing. is a full, clean concise, ,and 'exact description, referencebeingh'adtothe accompanying 4drawings,'forming apart of the' ' thisspecication.

' Myinyention relates to telephone exchange systems. .empoying'jelectrmagnetic switchdevices' 'for extending -callingflines and. hase number o'fobjects' and advanta es.V

Specification of Letters Patent.

- My .invention has for'one of itsobjects the? provision of means whereby llink connectors that. are te be serially connectediyith. calling .inestablishing telephonie connections willl'be so related tothe calling line extend-- vious-c onr iections.l Y i lnyention has'for employment of'priinary .master 'switches in .seekingrelation Vwith calling line's' .and secondary master switches in relation todii ing switching devices atcallin'g stations-that these latterdeyices vcan only operate to cause,

the 'addition of. succeeding extensions 'to .pre-

flines -g su'chfpresence,if the desired lines f are previously lousy, the desiredlli-nes are free from their-.previous-'service and are' restored to normal as, for example, in the case of desired subscribers stations Which Were prei viously called -or had. 'previously called,such

stations being immediately 'connected with calling lineswhen through with their p reitsurtli-er obj ect the ferent sets oiiline extensions .in'combination with switching 'devices for connecting line `extensions vwith.calling .linesv brought into cooperative relation WithV .the calling lines cedingfextensions when such preceding 'ex-- u tensions `havev been'- lconnected withl ,calling My ini'ention has 'for another -of its chel ects the proyision'of means'whereby calling .line extensions which have beenvbroug'ht tof ithe'. presence odesiredv lines .may remain in byfsaid 'primary and secondary --inaster' switches,these-secondary master switches f itsgroup';

liIyin-yention'has other objectsand' advan? tages and will be fully explained byjreerpertaining to' different groups of' lineextensions and .each common to the extensions Vof l rEnnrHoNY.

the preferred yembodiment "thereof ian-d. in 'Which Pannenhilfe-8,1915, .--Appiicationmednprii 5,"71913. Yserial No. 759,021'.

Figures. 1,2 and maken noname-ely am .1n numerical order With theonductorsgati,

the side margins thereof in alinement, illusf trate .an automatic telephone exchange systion.

.60 tem arranged in accordance with the inven- I'haI-'eshown'two suhstations 300 and V301 'having telephone stations to an'exchangel The equipment at -each o f these telephone condenser V3,4/ a telephone' receive v substationszincludesatelephone .switch hook.' '1,'fa callbell'2,"`a`

r4. and-"a .lines extending from'subf izo..

thesignal bell' 2 'and the condenser 4A3v in .bridge of .its associate telephone line-A and having an alternate contact ser'ying, When the telephone receiver is timely removed, to

Ainclude such receiver and .transmitter in another. bridge of the telephone line,4 the telephone bridge serving to permit ofthe passage of direct current 'While the lbell bridge serves to prevent such passage-.'-

l p One side of each telephone 'line includes many'circuit closing andinterrupting switchV arms '6, 7 8 and 9 as there-"are successive extensions tobe applied tocalling lines.' the switches .6, 7 and 8 serving to effect the operation of the first, second and' third selectors ll, 12 vand ldthat normally occupyfprede-A' termined'vk positions if'nleansv of coiled springs in order that ione of vthe telephone line sides may4 befcompleted through thev switch .arms 6, 7, 8 and 9. .The switch arms 6, 7, 8 an'd9 may be moved iromitheir line 'closing positions into engagement with those 'contacts in their complemental sets oft-con- While'the sWitcli-Qserves to eectthe f ipera. 'tion of a connector, these switchesoperating tacts 14g, 15, 16 and -17'th'at 'correspond rei spectiyely to the vgroups oi" thousands', groups of hundreds, groups vof tens, and theu'qits thatcorrespond to the number ofthe 'desired line and, inthe system shown., 'thel setsof contacts.- 14y`l7 each includes-ten Contact: points, adjacent contactszbeing4 suficiently separated so that the circuit controlled byeach, siyitchlgarm 'Will';.be. .ope`ned as said [switch arm moves from. one ContactA toanfother when' being. restored to its norinalpositioii." Each of the ratchet wheels 10,11,

12 and 13 has a magnet and spring Loontrolle'ddetent` 18,19', 20 and 21 Whichare pulled 'upon by springs to hold their 'assoreceiver l is upon its switch hook whereafter said receiver is removed whereupon the magnet 22 is first to operate to attract the 'detent 18 andrelease it from engagement with the i associate ratchet wheel '10 whereupon the .ment the magnet 22, which is designed slugswitch'arrn 6 is moved ina clockwise direction toward its normal position, this detent carrying a stop 26 which'is engaged by the arm-fwhfen this arm engages the Contact button ofthe set 14 next adjacent the con- ;ac t l: utto1 i engaged by saidl switch arm when in normal position. By this arrangegishly to release its detent 18 to prevent its operation while the arm 6 is passing from point to point, i s given suiicient time within Whichto release its detent 18 whereupon the stop 26 is drawn into ,register with a recess in the arm-6 to permit this arm to assume itsjfinal position, in which position the lineA circuit yis extended to the next arm 7 whereafter the magnet 23, the detent 19, and the stop 27 operate similarly to the magnet 22,

the detent, and the stop 2G finally to permit -the arm 7 to assume its "normal position i whereupon the linev circuit is extended to the switch` arm S'w'herea'fter the magnet 24:,

lthe detent 2O and thestop 28' operatesimilarly to the corresponding parts associated with the arms 6 and 7 whereby the arm 8 is extended into connection with the arm 9.` Thus the magnet 22 is individual tothe calling line extending switching device -having the arni`;7, the'ma'gnet 23 is individualto the calling line extending switching device having thea-rm 8, and the magnet 2a is in dividnal to the calling line extending switchingdevice having the -arm 9, inasmuch as the magnets 22, 23 and 24-opei'ate,.preferably though not necessarily in the manner described; respectively to, bring the arms 7, 8 and 9v into the line circuit. The magnet 25 is nov7 in circuit relation to permit the arm 9 to berestored to its normal positioufwhereupon the telephonebridge at the calling statiojn where the arms', 7, 8 and 9 4have been adjusted into engagement with their proper buttons 'for 41they purpose of calling the desired line is finally complete.' By the means illustrated the second and third selector Aswitches and the connector'switch areV not as 22,23, 24 and.

calling line.

cuit that has been *set into operationluntil the connector in the thousands group Vhas been selected, thev third-:Selector and connector switches are not set into' operation until the link connector in the 'hundreds group has been selected and the connector switch is ,not operated until the link connector in the tens group has been selected.` The equipments in association with Vthe arms 6, v7, 8 and 9 are' similar with the exception that the detent 2l is not mechanically connectedu'fith any stop and the corre# sponding arm 9'is, of course, not provided with any stop receiving recess. 'lhe calling subscriber having removed hisf telephone from its switch hook after he has set up the number of the desired line by means of the switchv arms, 7, -8 and 9, willcause aj series of operations which will now be described.

. A'. circuit -is initially establishedy w`hich is traceable from' the grounded' 'battery' '29,'

through the relay 30, the switclilioolr, tele? phonetransmitter. and receiver at the calling station, the s luggishly operating'magnet22,v

the aini- 6 and thebutton to which it Vwas" brought by the calling'subscribei, the lower armature switch of the relay 30 and the' left hand normal followup contact. of this arma.-

ture switch, the'resistance'I 31, of preferably five thousand ohms-to the common grounded rela;T 32. |Ihe magnet i22-will not operate through the resistance 31, the-operation off this magnet being deferred until the'rst link connector has been connected with the The relay-SOV- also will `not opera-te through the resistance-31,the opera# tion of this' relay occurring when the magnet 22 is operated. The resistance. of the elements 22, 23,24, 25-`a`nd 3() is vdesirably-two hundred 'fifty ohms each: Theresistance of the relay is desirably one ohni while the battery 29 is ,of fty volts.y The relay 32 will thus he' energized when includedin vthevir- .The lleft hand ics' armature switch of. the energized relay32 establishes a circuit traceable from the grounded battery 2 9, through the interrupter the left' handarinature switch of the' relay 32 and its4 then engaged contact,'the

left'h'and armature switch of relay 3l and its contact, the wiper 3510i: the master switch, the Waiting contact 36 witliwhich its wipersl happen to be inv engagement, the motornia'gnet 37, thenornial contact of theinterinediate armatureswitch of relay' 38, this armature switch,'to ground. Itshould be stated in passing that thev master switch that iiicludes the wiper 35 also has additional wipers 39, 40,41,.42 a`n l43 vwhich are adaptl f ed for engagement-with waiting contacts 44,

45, 46,47 and 48, these waiting" contacts together with the waitingfcontact'B vbeing indiridual to the motor magnet 37, there A being as '-niaiiy of these motorA magnets as,l

there are vsets of such .waiting contacts, saidv wipers normally restingzin engagement with Sonie suchl set of Waiting contacts and being moved from engagement'wit'h suchv set of 'waiting contacts into engagement With'- another set of such Waiting contacts-that' are individu alV to another and unemployed-motor 37v when the-master switch has performed its function in coopera-tion Withlthe :motor magnet 3zwith which it was lirst associated in,l extending acalling vtelephfni'e line.` Each motor ,magnet 37de individual to a-link A.confnec-tor which 1s' 'first to become connected' with -a .calling line, 'these connectors being connected Withcalling linesbefore the link connectors inthe thousands vgroups are'connected with the Vcalling lines, the linkA con-- 'nec'tcrs in the thousands groups being con'- 49, 50- and' 51, these Wipers being carriedby a `ratchet Wheel 152 which is operatedby -themotor -magnet'37 asthis motor inagne'tis vinterim'ttentlyenergized due to the action of the interrupter 33,- ',The link connectors havingthe Wipers 49,50 and lvarefdivided into vvthe-saine' groups linto 'which 'the motor mag;

nets 37 Vare divided so vthat'the vmaster switch 'having the Wipers 35,V etc., are cominonnot only to .the motor magnets 37 of agroup but also to the group of link V,conne'ctorshaving' this group 'of motcrma'gnets. Theniotoromagnet 37 will continue in operation'. until thefv'vipers 49, ,and '51 `have :engaged the' `Waiting contactsS., 54 and' 55. pertaining tol the calling line, these-'Wipers traveling over a plurality offsets vof these Waiting contacts in 4'seeking a calling line, `each of such sets pertaining to an``individual subscribers line. Similarly lpositioned ivaiting contactsoi the 'different` lines are in multiple-connection.inthe diierent switches. Whenthe Wipers'Ll-Q, 50 and 5l hare encountered the'waiting contacts 53, `54

and 55 or" a calling .linea. circuit established traceable from the grounded battery 29]. through the relay-30, one side ofthe telephone line, the telephonereceiver and transv:rnitterfatthe calling station, Vthe magnet 22, thersvvitch arin 6- and the button; upon which this switch arm fis resting,"the other'side of the calling line, the loive'r armature switch of relay 30 and its right hand normal follow-up' contact, the Waiting contact 552" .the Wiper 51 engaging the saine, .the Waiting Contact the Wiper -39- thenvengagingf the same, the-'left hand Winding of relay 34, the rightfhan-dv armature srv'itchof Vrelay 32 ,and 'its'vthenengaged Contact, toground. The circuit just traced does not include the resistance 3.1 and as the-resistance ,ofy the left hand, coiliof the relay 3 4. is;o'f one hundred 'ohms,current from the vbattery 29is per mitted to flow in'suiicient volume to energize the relay-3Q Whose armature switches-are attracted,the lower armature switchileaving its normal follow-up contactsand engaging its alternate contact,the Waiting'contact 54 being thus connected vvv-ith one""si de of the calling telephone` line, the'fwaitinig. "Contact 53 being permanently connected with'othe other sideof such 'liiie. Asjthe circuit-just traced. includes' the, 'relay' 34, the left fhand armature' fswit'chof 'this 'relay opens the-:circuit ot thenao'tor-` magnet 37'` Whose HWipers have encounteredjthewaiting contacts of the calling. line whereby 'these'` wipersremain in 'connection with.s uch 'waitingccontacts Y, The

'relay 34 beingV energized, af locl cing`icireu it is established traceable Afrom thefgrounded battery 29, throughthe relay 30, the 'waiting contact 53, the Wiper 4 9,'the upper-.armature switchof `relay A38 andi'ts normal-'folloiv-up Contact, the' Waiting contact 45, tlf1efwipe r 40, the; armature switch' oftherel'ay '34?, next adjacentto itswindings, the contactathen engaged vby this4 armature'v switch, to grounded right hand coil of :fthe-relay which is desirably of twenty-iiveghnndned' ohms resistance. Whenthe relay30g-fv energized the 'relay32 'and the resistanfcefl `were excluded from circuit at the' left 'hand normally follow-up Contact of the lov'vera'rmaturesuitch of relay 30,a' second* gap in the circuit ofthe motor magnet dT-being es tablished at theleft hand armature switchin the'relay 32 and thccircuit for-the left'- hand. winding of -the'relay 34 'being broken; at the rightA hand armature switch of relay 3 2 whereby thewipers 49, 50 and 51 of other callingv line seeking switches will not'remain in engagement- With waitixigcontacts that belong to thecallingline .Whose connectionisbeing described; The larmature switch of the relay 34 second to the right of its ,windings is included in circuit that contains the grounded battery 29, the relay 30,-0ne side of .thecalling line,'the`telephone receiver and transmitter of the 'calling line, the magnet 22 at the calling station, the arm 6 in the position to .which it has been adjusted by the calling .subscriber, the other side. of the calling line, thelcvfer armature switch of relay 30, the alternate contact of this armature 's ,ivitcln the waiting Contact 54, the

Wiper 5 0, the lowermost armature switch of relay 38'v-and'1ts normal Contact, the \va1ting contact 46, the vwiper 41, lthe saidl armature .switch or" the relay 34 andits Contact, the

relayv 56, of 'say two hundred fifty ohms resistance, .and the left handV grcuunded,armature fswltch of -thevr'elay'5'! and itscontaet,

The'relay 56 thereupon establishes auch;

55 is controlled by the switch arm 6 and the v circuit et thislmagnet is thereforebroken as thearin 6 is moved torardlitsnormal posi- A tionfwhich islillustrated;` The'inoreinent of thisswitch arm toward its normal position themagnet 22 is -ls'loyv to'relea'se, the disengaged-position' .of the detent'lS will not'be interfered with butrth'e relayl -56 'which is quich tojrespondv-'w-il-l' .openand'close the circuit-'for the motori-magnet 580i a setting up. switchcausingfthe Wipers-59,' :60 and 61 f to move intocoinijection with a .set of-Waiting contacts '62,f 63-` 6ifiiidivyidu`al' t`0 `the thou.- sands'groupof'lin'k connectors,oiie of which is'to lie-employed in the established connection, the d ilei'eiit sets of Waiting contacts 62,

` 63,564 'being individual to dii'erent thousands groups' of llink'connector's, While the 'Wipers 60V and 61l of' each setting up switchs (tlnre-` being 'sullicient'y of these switches ,for the tiaiiic of the system) having accessftofa'll of thefse'tsof contacts 62, 63.'

andG-l inthe systen'i.A l:"l`he. 'Wipers v59,' 60 `and 61 have been. brought into engagement with the desired (set of Waiting contacts 62,.

y. and; Giyvhcnfthe arm 6. has reached -'the 'contact butt-'onnxt preceding the .normal contact. button in the set 14 that is engaged the ar1ii'f6tocoiitmue one oli' the calling linejsidest'o the contact. arm 7 .The arm 6 is vlie'lda't thepoi-nt preceding vits final posil tionfby the Astop .26 until the magnet 22 is deiiergized,"a result which occurs When the,

-. desired group olf thousands has been-'found b'y theV sett-ing up A device having the Wipers 59,160 and 61 and'ivhicl'i result isdue tothe 'energization of the relay 57 then occurring, the armatureswitch 'of this relay opening the circuit Jtoi' the magnet 22 'Where'after the stop 26 is pulled into register with arecessv in the arm .6 vso, that this arm may be brought to normal position! in extending-its telephone farm 7. l p

lA primary master switch A andV a sec.- .ondary master switch B areindividual to lineA side'into 'connection with the switch eachother and each is common to a thousands group olink connect-ers. The primary master switch fr has Wipers x65, 66" vvhic'lrare adapted to travel over -sets of.

Waiting' .contacts 67, GS t-hat are individua-l to. each paii` oivaiting contacts 62, 63. The

Wipers 59,60 and 6l' are-stepped into-err.

vfgagement Aby the operation of the arm 6 with the desired set'of Vaiting contacts 62,

63 and. 6l irrespective of the position'- of the wipers 65, .H the 'Wipers 65, 66 are Abeing.employed in establishing anotherconn ection'the Wipers 59, 60 and 6l' will remain iii the position to. which they have been 'brought' Waiting for the release ol the wipers 65, 66 roiii'their previous employnient wlierca'ftcr ti "fgipers 65, 66 will be stepped arounduin l they engage the Waitingcontacts 67,68 thatare'now connected with `the Wipers 59 and 60, the' Wipers '59, 60u

alid 6l being permitted to remain asblong as need .be in'fthe positions to which they 'have been brought While 'Waiting for the release df the Wipers y65, 66 due tofthe alito-l -ma'tic'allydetermined delay ol:` the =move- :ment of the .switch arm 6to its final and normal position.` It the Wipers v65` and 66v are i iot in engagement with the selected waitmg contacts 67 and 68 these Wipers'are vbroughtl into 'such enga-gement, when. i'e-.

leased .from thenprevious employment, due to' the deenergization .of 'the'. .relay 69 that occurs, .inza manner to .be`statedwhen the Wipers 65.' and 66 are relieved of the previous employment whereupon 'the` lefthand armatureswitcl of relay 69 which lis 'common to the variousivaiting contacts ,6%.

establishes afcirc'uit for the motor .magnet 70 of 'the primary master switch, which circuit includes -the grounded battery 29,.the inteirupter 33,' the Wiper 161,. the. Waiting'l Contact 64: engaged thereby, the left :hand armature switch 'ofthe relay 69, the motor magnet 70, the lefthand, armature lswitch of`ielay71 and itsgrounded contact. When the vWipers` 65 and 66 'hai-'e been, brought intoy engagement With-the selected waiting contacts 67 and 68, the-,circuit of the motor magnet 70 is. opened ouiiig'tothe esta-b- .lishmentofa circuit including the grounded .battery 29, the relay 69, the .Wiper 66,.

the selected Yivaiting contact'GS, the selected Waiting contact .63, the wiper 60 andV tli'e grounded relay 57, this relay 57 being at this time Aenergized to open the circuit 'of the magnet 2,2 v'for thepuipose pr viously described. Battery being noia7 removed at the armature switch of relay 57 trom'the side 'of the calling line that lincludes the switch arms 6 and,7 the magnet 23 cannot .be operated to-permit the arm 7 to more toward normal until an idle link connector in the selected thousands 'group has been *constituted a continuation. ci Vthe calling line.

The secondary master switchB -has Wipers 72, 7 3, 74, 75 and 76 which normally' rest iii engagement with .soine set of Waiting contacts-77, 7 tain-to an idle link connector in the thousands group of link connectors to `which' this switch' B is common, theserf'ipers being adapted for connection with any of such sets ofwaiting, contacts 77, 78, 79, 8O and S1 belonging tothe different link .connectors in such lthousands group. switch B, when idle, is thusin position to take part in establishing' the connection of an idle'linlr connector in the selectedthouf sands group with the link connector lia-ving the Wipers e9,- 50 and 5l' that engage the Waiting contacts 53, and 55 of the'- calling line.

, 79, 89 and S1 .that'perl .120. `The in engagementwith a set of waiting cont-acts '77 Vto 81 andl assuming that the wipers 65 and 66 are'jinconnectionwith the selected waitmgconta'cts 62, and 63, a circuit is establishedfor the motor magnet 82 pertainmagnet-:which motor fmagnets are thus coininontothe secondary masterswitch B, the

CirQuitor" this Vmotor magnet 824 including the grounded battery 29,- the' interrupter- ,33, thefright hand ,armature switch oftherelay 59, the secondarmature switch to the left of the vWindii'igsi'ojrela'y 71, the Contact of Athis armature-' sivitclr,.tlie` wiper 72 of the switch-A 4havingV the wipers 49, 50 and laremultipled inthe presence of the wipers 85 and thousands group that have been selected 1 whereby each selector switch having the vwipers 85, 86 has access to said sets of wait- Ving-'contacts 87 and 88; A locking'circuit is now established for relay' 71' "which'is traceable fromthe grounded battery 29, the winding of relay of the callingline, the'waiting Contact 53 of the calling line, the wiper A 49 engaging the'waiting contact'53,"the uppermost armature switch of the relay 38 now 86 of the' selector switches pertaining vtothe w pertaining tothe calling line, the right hand *alternate*v contact Vof this arma-ture switch, the employed waiting contact 87, the wiper B, the waiting'contac't .77 engaged by 'this '85 engaging this waiting contact,l-the upperwiper, themotor magnet-82, .and-the ,inter- ,most armature switch of relay" 83 and its fao mediateA grounded 'armature switch' of the' `v normal follow-up contact, the waitingl-conrelay83 and the normal contact ofthis armature Switchs. The motor magnet 82 will ,operate the ratchet wheel 84 until' the wipers 85,' 86 carried'by this ratchet wheel are en'-.

tact 7 8 of the switch B, the wiper 73 engag-` ingthis waiting contact`,'the right hand armature'switchof the relay 7l that is-next gaged rwith thewaiting contacts. 87, 88 thattactof this armature switch,to the' groundare complementa-l respectively to the wipers ,49 and O'that are connected with the-calling line.V When the wipers 85 and 86 -thus' engage. the waitingf. contacts 87 and 88, the circuit 'of the` motorl magnet 82 is opened at the second armature .switch to theleft 'of the winding'so the relay 71 due to the establishyment of a circuit for'` this relay traceable froingthe' battery 89, Vthe ertremerightV handing` contact 67thewaiting contact 62, the

wiper 59, the switch' spring 90 now engaging its contact, the release magnet 9l,.bac k to the battery 8 9 whereby the wipers 85, v86 of the actuated motor magnet 82/ are permitted tcremain inl connection with thev waiting contacts 87, 88 that are lconnected withthe call-ing line. The. rel'easema-gnet 91 being included in the circuit just traced, vwithdraws the actuating pawlfof the motor Iinagnet 58 'from engagement' with the -ratchet wheel 92 thatcrries the wipers 59, 60 and v61 tov permit this ratchet'wheel to be restored to normal, the ratchet wheel carrying with it the. wipers 59, 60 and 61 to normal, the Vswitch spring, again being-removed fro engagement with its waiting contact so that the firstsetting upswitc'h is restored-to normal and-iii condition -tobe employed in establishi'ng another. connection. yThe waiting nrmtnots 87 and 892 nl: +11@ first link connectors ed right hand coil of the relay 71 whichl'may be oftwenty five hundred ohms resistance. The lockingcircuit is also established for Athe relay v38 traceable from the grounded battery 29, through the upper .winding of relay 38the uppermost armature switch oi Vthis relay and its two alternate contacts, the employed waiting contact 87, the employed wiper 85, the uppermost armature switch of. relay v83 and its normal follow-up contact, the waiting contact 78, the wiper 7 3thence l-by the two previously traced connections to the right hand grounded coil oth'erelay 71. YThe .top and bottom` armaturev switchesof the. relay 38 are thus maintainedin connection with theiralternate contactsfwhereby the calling line sidesare extended into connection with the waiting contacts 87 'and 88 and therethrough in connection with the top and bottom armature switches ofthe relay 83. 'The 'intermediate armature switch of the relay38, when'attracted, establishes a circuit Afor the motor magnet 93 of the master-switch having-the wipers-35, 39, 40, 41,' l2l and 4:3 whereby this motorinagnet operates the ratchet wheel 94 to bring these wipers into engagement with a set of waiting contacts pertaining to another but idley link connector of the group to which this station are nowin co erative relation with .the setting up switch the primary master The?" Aelements 7, 19, 23 and 27 -at the ca-llingsub-` 'I selected Ahundreds group wherebyaneid-le link ',fconnector'in such selected hundrods group connected with theemployed link connector Y inithe thousands' group wherebythecalling line .is extended into connection'v with ,s uch" employed connector in theselectedhun- ,y

-. dred group,v link; connectors. en -such h'unf` dreds group .beingfillu'strate'd .at F where? calling'substa'tion are 'noIW in, cooperative re-.

' v lation .with the-setting, up switch G, the pri-.

i mary master s'W i tch .H and "the secondary lmaster switch I Whichpertain' to .the vlink connectors in the selected'tens group Where-` an idle 'link connectory in; such selected tensgroup. is' connected-With the'employed link connector in tl ehundreds group Where- Eby the calling line is extended intocennec- "tion with such employed 'link connectorl in the selected tens' group, link connectors of, "such tens group being illustrated atpK Whereafter the elements 9,21, and 2 5 at the calling substation are nowl in. cooperative relation with the setting up switch L. 'The elements of thehundreds setting up switchV at the calling Asubstatioi'i' and which includel pa'rtsmarked 1, 11, 15, 19, 23. and 27 are co- 'operatii'ely associated With elements ywhich are similar in function andoperation to, the yelementsy thatcopera-te with the thousands setting up switching. device vat Ythe calling station 'which includes vthe partsmarked 6, 10, 1J ,18,;22 and 26, the elements whichcooperate Withf said hundreds setting up switch i v that "a re similar in function and operation to the'felements that' cooperate. with said thou-- -sands setting up switclihaving similar char- 40,

A added to each, L The elements of the. tens act'ers of `reference' but with a prime. mark l settingup 'switch at'the calling vsubstation and Which-include parts marked 8,' 1 2, 16, 20,

' 24' and-28are cooperatively associated with elements which are similar in function and' operation to the-elements that ecooperate with the thousandsfsettlng 'up j switching 'j devicel at'the calling station, the elements 'which cooperate 'with' "said tens setting up switch that are similar in function and operation to the elements that.' cooperate- With said thousands setting up 'switch having 'similar characters of' reference but with .the exponent 2 added to each." The elements lofthe units settingl up switch 'at the calling substation and which include parts marked; 9, 13, 17,' 21 and 25 arecoperatively asso- 'ciated with elements which are'similar 'in yfunction and'operation' tothe'. elements thatV coperateA Awith 'thethousands settingA up switching devices at'the calling station, the

elements -Which cooperate with said vunits setting up'fswitch that are -silnilar. 'in func@ tion and operation to 'the elements that cooperate with. said lthousands vsetting rup ence -but'. with the-exponent 3 added'-tcY each.

ing itsnornial 'position in iits clockwise movement, there`being. no occasion'. to 'delay' the restoration-:off the .'-lrm `l'9-v to' 'its normal position inasmuch. as tli'isfarni vis'to operate after the elements 8, 20, '24:jand 28 .atith'e A,

imnie'diateljffto 'associate the 'desiredline With-,the calling line.v The WipenS carried bythe ratchet Whee'l'923z is stepped'around as 'a consequence of thefoperat'ionsof the units setting up sivitchingidevice atv the callingA sta.tion until vit engages awaiting contact. 9G individual to the desired-lineWhereupon a circuit is. establishedthrough the motor magnet 97 to cause this inotbr lmagnet tooperate its ratchet Wheel 98 to bring the Wipers f.

99,1100 carried byv this lratcl'iet Wheelinto .engagement with the Wai-ting contacts 101,v

1 02- of-"tlie desired line? 'The circuit'eestablished 'for the motor. magnet' 97'" is traceable from the ,groundedb'attery 29, the interjrupterthe switch Aspring l03and the contact-initially. engaged thereby when ,the

ratchet.. wheel iras. vfirst operated, the vri per' .104 of the l secc n-dary master switch.

. I, the uniting contact enga-ged by this Wiper,

the' :not-or magnet.v 97,", the'intermediate armature switch ofthe relay 8 32 and itsiight hand,` normali follow up contact, to ',grollLn'd.'l

When theliwipers''). 10Q engage the' {valiting contacts '101, 102 thatlbelon'g tofthe saine line that -ha's'the' ivaiting-Zcruitact' 96" engaged ybyg'th'e wiper '-95',' the circuiti-othe Amotor `magnet '9T Will vhe opened lat the right hand normal Contact of the intermediate armature switch of the relay 832 if the desired 'line Ais idle"'wliere by the Wipers 99,100 SWil-l be arf rested Ain engagement Withthe desired wait", ing contacts 101,1'102, circuit tcrthe'rela37 S thereupon being-established, this circuit beingtraceablev from vthe battery'- 893, 'the extreme'right' hand arinaturelsufitch ofthe relay 7 2, the alternate contaot'of this ar mature switch, the .Wiper 752., the Waiting contact S02 engaged thereby, the vlowermost Winding of the' mieu-832,' the rightl hand armature 'switch 'of relay ,105 .audits normal contact,the lou'c'rmost armature switch .of rela)7 106Lan'd its normal follow-un contact,

gaged Contact, assuming that; the desired '$03 -whereupon the releaseinagn'et 913.jis en -I ergled to Arelease the ratchetl -Wheel .923 to ythe Wiper 100, the Waiting conmigo-102 eno gaged thereby, the upperswitch of'the'd'evsired subscribers relay/wand vits then er1- line -is idle, the engaged Waiting contact'96, 'the Wiper 95 engaging this waiting contact,- thea-'Witch 903 and its then engaged contact, Ithe 4release'magnet 913. back to thebatter)V7` v pei-init the 'wiper 95' tobe restored'toanormal' :mdto permit the'switch springs 903 and.

ioV

that 4may .loe restored to normal are notadapted to be used in setting up other co'nnections untilf their controlling vmaster switches have'been stepped off of the wait# 'which thereupon establishes a locking circuit for itself traceable from the groundedbat.- tery 29, the upper. winding oi" the `relayf106,. the intermediate 'armature switch f .of this 'relay and its then engaged' contact, lthe intermediate armature switch of the relayy 832 and its alternate contact, to ground. The

top and .bottom armatureswitches ofN the relay. 10.6 now'serv'e'to engage their alter nate contacts to continue the calling line contacts with Vwhich they are connecte/sides into connection with the wipers 99 and ed. Y'If'the desired line is busy the wipei/s 99 and 100 will continue' in operation either vuntil the calling -subscriber restores-his telcphone upon its. switch hook or untilthe previously 'busy vdesired subscriber restores his l telephone .upon l its switch hook whereupon' the'relay 30 of 'such desired linewill be deenergized to permit its upper armature switch. to' engage its contact whereby vthe wipers .99, 10o may become connected with the desired line. When the relay 832 is eilergized Vit establishes' circuit through the leftV hand winding of .the relay 105 which.

circuit is traceable from the grounded intermediate arinatui'e switch Hoi'f the relay 832, the

alternate con-tact of. this armature switch,

' the left handwinding of the relay 105, having say' a resistance oi two hundred fifty ohms, the. lcwei'most armature switch of relay'8"3 2 and its alternate contact, the wiperv 862, the waiting contact 882, tl'ienc'e by obvious connections over both sides of the call.- ing line to the grounded battery. 29, by way of the winding' of relay 30, the up er windings of relays 38, 83, 831 -and 832, these'relay windings being thus -in parallel relation. This circuit, including its multiple paths, constitutes a holdingT circuit for'the various relay windings` included therein. The left hand armature swit'chof the relay 105 now Aestablishes a circuit for the 'motor magnet 933. to moya the wipers of the master switch the waiting contacts engaged therefby into connection with the succeeding set "cfwaiting contacts connected with an idle link connector inthe tens group to which the .switch l iscommon.

mature switch and its alternate contact estalolish a .circuit for the lower winding of relay 1061' whereby the 'ringing generatorVV 107 is included in circuit with the signal bell at the'desired station. rlhis lower winding of the relay-106 .may be of twenty ve hundred ohms resistanceY so that.- the relay 106 will not be vmp'i'erated when the current l the ringing current' flowing through .the

lower winding of the' relay 51.06' willl be sufcientlyfincreased toenergize. this relay The right `hand ar-V vwhereby telephonie connection Abetween the calling and called stations iscomplete.

station by a circuit rtraceable' from th@ groundedbatteryf29, -the relay 30j`of the.

called line, both sides of the `calledvline,the

.Talking current is supplied to the. calledthe relay 106 and its alternate contact, the y right hand -winding of relay 105,' the inter-v mediate armature switch of relay. 832 and its alternate contact to ground, the relayO of the called line being at the same time energized to prcrent it from heing'selected by anotherv calling line while. telephon'icaflly connected with the rst c :allin'g line. It should' be. observed .that the relay 30 of the called line is maintained f energized while calling current is passingoi'er thc called line by a circuit traceable -from the grounded battery 29, the'windiiig of said relay 30, the

n-faitiiig contact 101 ofthe called line,;the f wiper engaging this waiting contact, the uppermost armature switch of the relay 106 and its normal contact, the intermediate armature switch of the relay 832 .and its -al-v ion tornate contact to ground whereby lringing current' v'willilow through the lower armature switch of therelay 80 'of the called line and its alternate contact. scrihers are through conversation they. restore .their telephone receivers to their switch hooks whereupon their .relays 30 are' denergized, the relay 10.5 vis denergized,

energized causing the equipment to'be ref; stored to.. normal,` it being understood that,

in the embodiment of theinycnti'on shown,A the wipers of theyarious selector switf'zhes.v

individual' to the link connectors may remain in engagement with the 'waiting contactscnlVhen the sub- .and the relays 38,83, 831 and S32-are deizo gaged therelc-yluntil another v connection is being established though the-invention is not to be restricted to this characteristic.l

.The calling -line 'extending switching devices are illustrated .as- `including 4'distinct lelectrc---magnets 22, 23, 24 and '25 for the* salr'e of simplicity of. illustration and the switch arms 7, 8 and 9 are shownas beingv adapted. for. direct manual operation, also. for the salie of simplicity of illustration, but

i it, will hefappareiit. those. skilled in :the art that operating equipment' may be eiii.

ployedwhich is .net liniite'd tosuch charac teristics. The delay in' the 'operation'ol lthe callingline extending swit'ching'fdevicesat.v the calling stationsis desirahly'secured,fpa1

' Iticularly*in theeinbodiinent of thejiiivention herein shown', by .pro.v iclingal plurality of switch :arnis 6, 7 and 8 butthis is nchar 'zi`cte,iisti'c to which the invention :is` not to be lirn'ited I t: 4is also apparent from "Q theV description of the preferred'embodimentof the invention given thatl there, are many. features of the inventionthat are .not to be restrictedto those systems vby ivhichconnec- .tions may he established hy -a-pparatus'ata calling station with desired stations and the invention not 'therefore to be limited to systems-.that are purely automatic, -noris the system tobe limited to 'one in'whichthe' call ing stations are Substations of subscribers lines that `extend toan exchange.

It is .obvious that inaiiy' changes may be -n'iade the preferred 'embodiment of my .invention Vherein Aillustrated .without depart# ing freni th'efspirit of .the inyentionand I do. not ltliereor-ewisliv to .heliinited to the iiecise' details of. vconstruction.and'circuit ar- Having thus described my invention I u. t rs Patent the folloivinggg-f l. A telephone exchange systeinincludin-g telephone lines extending fronisubstations 35y to anexchange'; extensions for such telephone lines adapted .for connection therewith in successive order; successively open ating electro-magnetic switching devices respectively cooperatively related with, .the

successively related extensionsin their order .andin the order of operation of said electromagnetic switching devices and operating in' succession for connecting such extensions in successive order with-calling telephone lines; successively operating calling. line extend.- ing switching devices at each of thesubstations of said telephone lines that are respectively adapted for operative association inthe order of their succession-with the suc.

cessivelyoperating electro-magnetic switching devices in the order of succession of the latter; and electro-magnetic means whereby the'calling line extending switching devices which succeed the irst at a calling station aresuccessively brought into cooperative relation 'with'their line,A and 'operated by the.

extensions associated with preceding calling line extending switching devices for. this purpose when suchextensions are connected 'Y .with the line of such calling linegextending switching devices.

y 2f A telephone exchange system including .telephone lines extending from lsubsta'tioris 'to an exchange; extensions for such telephone'lines adapted for connection .theresuccessive order; successively operating electromagnetic switching. devices; respectively -coperatively related with the successively related extensions in their'. or-

der. and', 11,1- the ord'ernfi' Operation' 0f. said.

Electre-eignen.anche f devices and. .0P- I .erating insuccessi'on for' connect-ing such ex- Y tensions in 'successive' -forder .with .calling :telephonelines successively operating call# .ing line extending -switclng devices at each fofpthe sulostations l*of said telephonelin'es 'that are. respectively adapted for joperativeassociation the'worder jefoir"succession` with .the successively' operating electro-mag .net-ic switching devices the 'orden-of succession of ther latter.; kelectron'iagneti- 'cally controlled devicesavtihereby the calling line extending switching. devicesy which sueceed theI first 'at a calling' station',` and\ tov which' succeeding". calling aline extending.

. switching" 'devices 'jfsaid' electromagnetically controlled .devices are f i-ndilviduail,-. are,` successively brought -int'of ebperati-ve" j relation ycontrolled devices beingv respectively foper'- ated .inf succession .by the`extensions`associated .with preceding calling lineextendingswitching devices Afo'r-.thi's 'purpose 'when such- 'extensions are connected with the line of such callingline lextending switching devices..

3. `A telephone exchange systeni including v telephone lines extending from substations to an exchange; extensions for suchtele' phonev lines adapted orco'nnection there#y with in successive order; 'successively operating electro-magnetic switching devices re.- spectively cooperatively relatedl with successively 'related extensions v.intheirorder a-nd'in the order of operation of said electroin succcssionfor 'connecting suoli extensions in successive 4order 'withcali-ing telephone lines; calling line 'extending .switching devices at stations. of said 'telephone lines `for -erate to connect succeeding extensions with .thepreceding extensions. 4, -A- telephone exchange system including' telephone lines whose. stations; when calling,

vare tchave telephonelinc. extensions .conJ

nected tl'ierewith; v extensions for-such telephone lines adaptedv for connection, there- 'with in l successive order. successivelyl operf ating electro-,magnetic switching 'devices Jre-4 specti-velycooperatively 'related- 'i'vith 'the successively related extensions in` their' order magnetic switching devices .and operatingtensions are' connected tensionsiii successive order with calling telephone lines; successively operating calling line extending switching devices at each of the substations, of. said telephone' lines that` iare respectively adapted -'for operative association-in-th'e order ottheir succession-with. f: the successively operatingv electro-magnetic switching devices'in the order of succession of the latter; and electro-magnetic .means whereby the callin'g line extending switching devices which succeed the first at a' calling stationA are successively brought into cooperative relation with their line and oper'- ated by theextensions associated withlpre-4 .ceding calling lineextendin'g switching de vices forthis'purpose .when such extensions,

are connected with the line of such callin line extendingfswitching devices.

.' A telephone exchange system including are to have telephone line extensions i connectedrtherewith; extensions for such telephone :lines `adapted for connection therev lwithinv successive order; successively oper- 'ating electromagnetic switching devices respectively coperatively related with .the

successively related extensions in their order and inthe order .ot operation of said electro-magnetic switching ldevices. and operating in succession for ,connectingy such extensions in successive order with callingtele? phone lines; successively operating calling linel extending. switching devices at each or the sribstations of; said telephone lines. thatl .are respectivelyadapted for operative vas sociation in theforder oftheir succession with the snccessivelyloperating electro-magnetic jswitching"'devices in the order of succession of' the latter; gland `electro-magnetically controlling deviceslwhereby the calling li-ne'extending switching devices which. lsuc- 'ceed the irst at a calling station, and to which. succeeding calling .line lextending switching devices said electro-magnetically controlled devices are individual, are successively brought into coperative relation with Y their line, these electro-magnetically conl trolle'd devices being respectively-operated in succession by the extensions associated with preceding `callin g line extending switching dev'ices*-or this with the line of such calling line extending switching devices. 4 l

GQ A telephone exchange system including telephone lines extending from substations to an exchange settingiip switches adapted for4 operation hy calling stations; primary master switches adapted to be selected 'by the setting up switches' and which in turn areadapted to select employed setting up switches; secondary master switches cooperatively related with the primary master iii-pose 'when such exvmechanism4 forconnecting an idle extension of a selected set with a calling line,'there being calling station equipmentv for operatingsaid electro-magnetic switching mechanism and coperatively associated Vwith suchv electrofinagnetic switching mechanism by employed setting up, primary-master, and

- secondary master switches.

' 7 A telephone exchange systemincliiding i telephone'lines extending from' substations to an exchange; setting up switches adapted for operation by calling stations; primary l masterV switches adapted to be selected by v telephonelines whose stations, .when calling,

the setting-'up switches and which in turn 'are adapted to select employed setting up ing mechanism fon connecting an idle extension of a selectedset with a calling line,

there being calling station equipment for operating said electro-magnetic switching mechanism and coperatively vassociated 'withsucli electromagnetic switching mech* anism by employed setting up, primary master, and secondary. master, switches.

8. A telephone exchange system including telephone lines extending from substations to an exchange; setting up switches adapted for operation by calling stations; primary master switches adapted to-be selected by the setting up switches and which in turn are adapted v to select employed. setting' up switches; secondaryl master switches coperatively related with the primary master switches and coperatively related by-saidprimary master switches with employed setline extensions to the extensions of each of which sets a secondaryma. er switch is coniaanl . ting up switches; a plurality of sets of calling mon whereby saidl secondarynaster switches i,

are enabled toassociate idle telephone line extensions ci? selected sets with calling lines; and electro-magnetic switching devicesl individual to saidextensions for connecting the same with calling lines., there being calling station equipment toroperating said electro; magnetic switching devices and coperatively associated with such electro-magnetic switching devices -by employed setting up; primary master, switches.

9. A telephone exchange system including: telephone lines, extending from siibstations to an exchange;setting up switches adapted for operation by calling stations;- primary master switches adapted to be selected by the setting up switches andwhich in turn are adaptedv to select employed setting up switches; secondary master switches coop-- eratively--related with the primary master switches and cooperatively. related by said .primaryfmast'er switches with employed setstation equipment for yoperating said electro-magnetic switching devices and cooperatively associated with such electro-magnetic switching ldevices by employed setting up, primary'master, and secondary master switches.

10. A telephone exchangesystem .including telephone' lines extending from substations to an exchange; setting up switches adapted for operation by calling stations; primary master switches adapted tov bese-y lected 'by the setting up switches and which in turn are adapted .to select employed setting up switches; secondary master switches cooperatively related witli-the primary inaster switches and cooperatively related by said primary master switcheslwith employed setting up switches; a yplurality of sets of calling line -extensionsytol the .extensions of each of which sets a secondary'iiiaster switch is commomvvhereby saidsecondary master switches are enabled to associate idle. tele: phone line extensions of selected sets with vcalling lines; electro-magnetic switching mechanism 4for connecting an idle extension of a selected set with a 'calling.line, there being callingstatio'n equipment for operating said electro-magnetic switching mechanism a'iidcoperativelyl associatedv with such .electro-magnetic I switching [mechanism by employed setting up', prima-ry master, and secondary .master yfjsvvitches; and -meaiis whereby each; secondary master vswitchV is normallyl cooperatively related with 'an idle extension of itsset of extensions and is ref ployedlsetting up, primary master, and sec' .130 n moved fromsiijcli coloperatiie relation when it 'has been'employed to connect an extenand secondary master -sio'ii 4with a calling lineland is thereafter Abrought .into cooperative relation With 'anvadapted for operation by calling stations;

primary "master switches adapted to be selected bythe setting up Iswitches vand which f in turn are adaptedto select 'employed setting up switches; 'secondary master switchesV cooperatively related .withthe primarymaster switches and cooperativelyrelated by.

said primary master switches with employed setting up switches,'"each secondary masterv switch having a 'primary master switch individual thereto; a plurality of. sets of calling line extensions to the extensions of each of which sets a secondary master switch is common, whereby .said secondary master A- switches are enabled to associate idle telei phone'line extensions -of selected sets with calling lines; electro-magnetic switching.

mechanism forconnecting an idle'exte'nsion of a' selected setwith a calling line, there be# ing calling station equipment for operating employed setting up, primary master, and secondary master switches; vand means whereby each secondary -master switch 'is said electro-magnetic switching mechanism y and cooperatively associated with such electro-magnetic switching mechanism by normally cooperatively related. with an idle l extension of its set of extensions and isl removed from such cooperative relation'when it has been employed to connect an 'exten sion with a calling line and is thereafter brought into cooperative relation with afnother idle extension. l

l2. A telephone exchange system includ ing telephone lines extending from sub- 'statioiis to an exchange; setting up switches adapted for operation by calling stations;

primary master switches adapted to be selected by the setting up switches and which iio ter switches and cooperatively related by said primary master switches .with employed setting iip switches; al pluralityv oi'sets' of calling line extensions to the extensions of .each of which sets a secondary master switch is common whereby said secondary master switches are enabled to associate idle telephone .line extensions of' selected sets with calling lines electro-magnetic 'switch-A ing devices individual to said extensions for ,electra-magnetic switching .devices by emondarylmaster switches; and means wherevby each secondary master switch is norm ensayar coperatively'related with an idleexten of its set of extensions and is removed from Vsuch coperative relation when it has been employed to connect an extension with a calling line and isy thereafter brought into cooperative relation withanother idle ex*- tension.

13.y A telephone exchange system including telephone lines extending from substations to an exchange; setting up switches adaptedfor operation by calling stations; primary master switches adapted to be selected by the setting up switches, and which in turn are adapted toselect employed setting upswitches; secondary mas- .ter switches cooperatively relatedwith the primary masterswitches and cooperatively *related by said primary master switches with'employed setting up switches, each secondaryv master switch having a' primary master switch individualthereto; a plurality ofy sets of calling line extensions to the" extensions of each of. which'sets a secondary master switch is common whereby said secondary master switches are enable to associate idle telephone line vextensions of selected setswith 'calling lines; electro-magnetic switching devices individual to said extensions for connecting the same with calling lines, there being calling station equipment Y for operating said: electro-mag# netic switching devices and coperatively associated with such electromagnetic switching devices by employed setting. up7 pria mary vmaster,- and secondary master switches; and means whereby each secondary master switch is normally cooperatively related with an idle extension of its set of extensions and is removed from such coperative relation when it has been employed to connect-an extension with a calling line and is thereafter brought into cooperative relation with another idle extension.

14.v Atelephone exchange system including telephone lines extending from substations to an exchange; primary master switches in seekingrelation to calling lines ;A secondary master switches cooperatively related with the-primary master switches; a plurality of sets of calling line extensions tothe extensionsof each of which sets a secondary master switch is common, whereby said lseconda-ry master switches are enabled to associate idle telephone line extensions of selected sets with calling lines; and electro magnetic switching mechanism for connecting an idle extension of a selected set with a calling line, there being .calling station equipment for operating said electro-mag netic switching mechanism and coopera@ tively associated with such electro-magnetic switching mechanism by employed primary master and secondary master switches.

15. A telephone exchange system includassociated with es extending from*snhsamA lated with vthe' primary master switc each secondary master switch having alpi mary'master switch individual thereto.; plurality of sets or' calling line extensie; :s theextensionsof sachet whichsets secondary master switch is common, ,whenby said secondarymaster switches are en' abled to associate idle telephone line extensions oi selected sets with calling lines; and electro-magnetic switching mechanism for connecting an idle extension of aselected setwitha calling line, there being calling station equipment'for operating said electro-magnetic switching mechanism and co operatively associated with such 'electro-v magnetic switching mechanism'by employed aff primary master and secondary switches. 16. A telephone exchange system includ ing .telephone lines extending from substations to an exchange;' primary master switches in seeking relation to calling lines; secondary master switches coperatively re lated with the primary master switches; plurality of sets of calling line extensions to the extensions of each offwhich sets a sec-` o ndarv master 'switch is common whereby said secondary master switches are enabled to associate idle telephone line extensions or selected sets with calling lines; and-electromagnetic switching devices individual to said extensions for connecting the same with calling lines, Vthere being calling sta-tion equipment tor Y operating said -'electro-magnetic switching devices and cooperatively such electro -magneticY switching devices by employedv primary master. and secondary master switches.

l?. A telephone exchange systemincludn ing telephone lines extending from substa tions to exchange; primary master switches in seeking` relation with calling lines; secondary master switches'coperatively related with the primary 'master sf-,vitches9 each secondary master switch haw ing a primary master switch individual thereto; a plurality oll sets of calling line extensions to the extensions of each .of which sets a secondary master switch is commen whereby said secondary master switches are enabled to associate idle telephone line extensions of selected setswith calling lines; and electro-magnetic switching devices ina diridral to Asaid extensions for connecting` the same with calling lines, there being ca ing station equipment for operating "an electro-magnetic switching'devices andcoiperatively associated with such electro-magnetic switching devices by employed primary l 4' 50- switches; yand means whereby each seconding telephone lines extending from substations to an. exchange; primary master l switches irrs'eeking relation to calling lines;

seconda-ryinaster switches cooperatively related with'tli'e primary' master switches; a plurality of sets'of calling line extensions to theextensions of 'eachA o f whichv sets a sec- -ondaryma'ster switch is common, whereby said' secondary 'master switchesf are enabled to associate idle telephone line extensionsof selected sets. witli calling Jlines; electro-magnetic switching' mechanism for-connecting an' idle extension' of a' selected set with a calling line, "there .being calling -station equipment forbperating' said electromag ln etic yswitching mechanism and coperatively associated-with such electro-magnetic- .switching f mechanism by. employed primary mai-ster and secondary master switches; and

means 'whereby' each secondary master- Switch'tis y'normaliy coperatively related with an idlef'extension' of its setoi1 exten- ,s ions'and is' removed "from such coperative relation when it-lias. been employed -to connect an extension with'a calling -line and is thereafter broi'ight into cooperative relation with another idle extension.

19.- A telephone exchange system" includ ing telephone-lines,extending from substations to I'auf exchange; primary master switches'in seeking relation to calling lines;

secondary Imasterswitches coperatively related with the primary .master switches,`

each secondary master yswitch' having a pri# mary masterfswi'tch individual thereto; a plurality of setsmofcalling line extensions to the extensions of `each oi' which.- sets' a secondary 'iiiaster ,switch is common, whereb v said secondary master switches are en-.

abled to' associate {idletelephone line extensions of selected sets with calling lines;

lelectro-magnetic switching mechanism for 4connectingfan idle extension of. a selected'. set with a' calling line, 'there being lcalling station equipment for operating said electro- 'magnetic switchingjmechanism and copra-tively associated with such electro-magnetic switching mechanism by employed 'primary master, andl .secondary master ary-master'switch is normally cooperatively v"related with an idle extension of its set of Y'extensions and Ais-` removed from such co-vl the' extensions ofeacli of which sets a secl Aequipment for .operating said electro-magnetic. switching devices and cooperatively associated withl such switching devices by employed primary master and' secondary master switchesgfand means whereby each` secondary master switch is normally cooperatively Vrelated with an idle extension of itsaset of exten- 30 sions and is removed from fsuch v7copera'tive relation when it has been 'employed'to'fconnect an extension vWithv a calling 'line "andfis thereafter brought into'coperativerelation with-another idle extension. i

21. A telephone exchange systeiii'includ ing telephone linesvextending :from substations to an exchange;v primary 'fmaster switches in seeking relation to'l calling' linesy v secondary master switches cooperatively re- 9'0 lated with the primary. master" switches, each secondary .master switch having a primary master switch individual .thereto; 'a plurality of sets of calling 'line extensions to the extensions'of each- `of"'wlii'chsets'-a 95 secondary master switch iscommon wl'iercbysaid secondary master switches are `-enabled to associate lidle telephone lineextensions of selected sets with calling lines; -electrosmag'- netic switching devices individual'to said. 100.

extensions for connecting thefsame with calling lines, there being calling' station' equipment for operating said electro`-mag netic .switching devicesand vcopera'tively associated with such electro L-magnetic ,i105 switching vdevices by employed' 4priiii'arymaster and secondary'in'aster-switches;fand incanswhereby veach secondary n iaster switch is normally cooperatively related'- with'y an idle extension of itsset of extensions andlis 110 removed from such cooperative relation when it has been employed to connect an extension with a calling line and is thereafter brought into cooperative relation withan'other idleJ extension. 22. IA telephone exchange systemfinclud ing telephone lines extending fromif'sub'staf tions toan exchange; extensions'jfonsuCh telephone lines adapted for connection thereL with in successive order; successively oper- 120 ating electro-magnetic switching devices "re-f spectively coperatively related" with the successively -related extensions in t-heir'fordcr and in the order of operation of said electromagneticswitching devices 'and op' e1-atingIv 125 in succession for connecting such extensions in successive .order withI calling -telephonefkr lines; successively operating calling-line: xii tendingfswitching devices a-tea'ch ofth'e'"ub stations of 'said telephone lines-that electro #magnetic i incise? `spectively adapted for operative association in the order of their succession with the successively operatnig electro-magnetic switching devices in the order of suc ession of the tions to an exchange; extensions for such telephone lines adapted for connection therewith in successive order; successively operating electro-magnetic switching devices respectively cooperatively related with the successively related extensions in their order and in the order of operation of said electromagnetic switching devices and operating in succession for connecting such extensions in successive order with calling telephone lines; successively operating calling line extending switching devices at -each of the substations of said telephone lines that are respectively adapted for operative association in the order of their succession with the successively operating electro-magnetic switching vdevices in the order of succession of the latter; and electro-magnetic means whereby a calling line extending switching device which succeeds the first at a calling station,

xsbrought into cooperative relation with its line when said first switching device has performed its function.

' 24. A telephone exchange system includling telephone lines extending from substations to an exchange; extensions for such telephone' lines adapted for connection therewith in successive order; successivelyoperating electro-magnetic switching devices respectively coperatively related with the successively related extensions in their order andin the order of operation of said electro- -magnetic switching devices and operating in succession for connecting such extensions in -successive order with calling telephone lines; successively operating calling line extending switching devices at each of the sub- 'stations of -said telephone lines that are respectively adapted for operative association in the order of their succession with thesuccessively operating electro-magnetic switching devices in the-order of succession of the latter; and means whereby a calling line extending switching device which succeeds the rst at a calling station is brought into cooperative relation with its line when said rst switching device has performed its function.

Q5. A telephone exchange system including telephone lines extending' from subscribers stations to an exchange; linl; connectors ifor uniting lines in conversation; electromagnetic connector switches including travcling wipers for uniting desired lines with said link connectors; and means pertaining to the telephone linesand governed thereby whentlieir lines are to be called for continuing the wiper of said connector switches in operation toprevent them froiii connecting the link connectors with desired lines when such lines are previously busy and tor thereafter stopping the wiper of said connector switches to connect said link connectors with previously busy desired lines when the receivers at their stations have been restored upon their switch hooks. i

26. A telephone exchange Vsystem including telephone lines extending from subscribers stations to an exchange; extensions for such telephone lines; link connectors for uniting calling lines with said extensions;

electro-magnetic connector switches including traveling wipers for uniting desired extensions with said link connectors; and means pertaining to the telephone line extensions and governed thereby when previously taken for use for continuing the wiper of said connector switches in operation to prevent them from connecting desired link connectorsv therewith, and for thereafter stopping the wiper of said connector switches to connect said linlr connectors with previously busyextensions when released from their previous use.

27. A telephone exchange system including telephone line extensions; electro-inagnet'ic connector switches including traveling wipers `for including desired extensions in telephonie circuits; and means pertaining to the telephone line extensions and governed thereby when previously taken for use for continuing the wiper of said connector switches in operation to prevent them from connectingdesired extensions in telephone circuits; and for thereafter stopping the wiper of said connector switches to include desired extensions in telephonie circuits when such extensions are released from' their previous use. y A

ln witness awhereof; I hereunto subscribe my naine this thirty :first day of March A. D.,

G. B. Cnaccg. E. L. 'Wiiirn 

